Opinion on M50 head lifetime

[granit_silber]

i'm from malaysia and own a manual transmission e34 520i 24v on a m50 non-vanos engine.

the car is now touching 221,000 km ~ 131,000 miles.

questions then:
1. for this particular m50 non-vanos head, what are the frequent problems/fixes ?
2. what coolant besides bmw blue coolant would be best (phosphate free etc)

1. Mine has 175,ooo miles on it with no problems.
2. There aren't any

-ashley